Astronomers can now predict an oncoming supernova just a few years in advance

A team of astronomers believes they have found an effective method for predicting a supernova, a report from Space.com reveals.

While stars do expand to massive sizes and become red giants before their demise, we have had no way of knowing how long it will take for a red giant to go supernova. It could take hundreds of thousands, if not millions, of years.

All of that has just changed though, thanks to a team of astronomers that has devised a method for spotting stars that are likely to supernova within only a few years — a tiny fraction of time in the context of astronomy.

Going supernova

The team, who published their findings in a paper in the preprint server arXiv, have had their work accepted for publication in the journal Monthly Notices of the Royal Astronomical Society.

They highlight a few tell-tale signs for a supernova — namely, if a star is giant and red and surrounded by a thick shroud of material, keep away — it will likely explode in a dramatic life-ending supernova within a few years.

As it nears the end of its lifetime, a star stops fusing hydrogen and begins fusing heavier elements, such as carbon, oxygen, and silicon. The star eventually starts to form iron, which marks the beginning of the end of the star. As iron doesn't release more energy than it takes to produce, the star will quickly deteriorate and explode into a massive supernova.

Despite the dramatic change going on inside a star's core before a supernova, it's hard to tell the status of a star from the outside. The new method devised by the team of astronomers, however, may help others in their field to pinpoint stars for observation so as to view a supernova in real-time.

Pinpointing explosive giant red stars

For their investigation, the astronomers studied a few dozen examples of a unique type of supernova called a Type II-P supernova. What sets these apart is that they remain bright long after the initial explosion has taken place.

By looking back at old image catalogs, they were able to trace back images of a few stars before they exploded. All of these were red supergiants, much like Betelgeuse — one of the largest stars visible to the naked eye, which is due for a supernova itself.

What's more, the stars all developed dense shrouds of surrounding material a few years before they exploded. These shrouds were much denser than the material currently seen around Betelgeuse, suggesting that the star may still have a bit of time left before going supernova.

Using simulations, the researchers found that these shrouds can form decades before a supernova. It means that, if an astronomer discovers a giant red star partially obscured by a large shroud of material, they may have found a star that's very close to going supernova. Or, at the very least, they can narrow it down to a few years rather than a few millennia.